public class test1 {
    //力扣  69.x的平方根
    public static int mySqrt(int x) {
        if(x<1){
            return 0;
        }
        long left = 1 ,right = x,mid = 0;
        while(left<right){
            mid = left+(right - left+1)/2;
            if(mid*mid<=x){
                left = mid;
            }else{
                right = mid - 1;
            }
        }
        return (int)left;
    }
}
